Teor de água inicial e teste de envelhecimento acelerado na avaliação da qualidade de sementes de milho-doce

Abstract

Vigor tests allow additional information about physiological potential of seeds, which is essential to compose seed quality control programs. This work was carried out in order to evaluate different drying methods to adjust the moisture content on sweet corn seeds and combination exposition periods and initial moisture content in the accelerated aging test. The assay was conducted with five lots of sweet corn hybrid seeds Tropical Plus (sh2) and divided into two steps. The first step consisted in the evaluation of drying methods to adjust the moisture content: drying oven regulated at 38°C, silica gel, saturated sodium chloride solution (NaCl), saturated potassium carbonate solution (K2CO3) and saturated potassium hydroxide solution (KOH); water content, thousand seeds weight and hectolitre weight. On the second step, were performed the following evaluations: accelerated aging test with adjust of initial moisture content in 14, 12 and 10% by drying oven method at 38°C, evaluating three exposition periods (48, 72 and 96 hours), seed water content, thousand seeds, standard germination, first counting, field seedlings emergency, electrical conductivity, earliness of primary root emission, cold test and traditional accelerated aging test (48, 72 and 96 hours). The experimental design used was totally randomized where comparison between medians of lots was performed by Tukey test, at 5% of significance. Results indicated that drying oven method at 38°C was the most efficient drying of sweet corn seeds, with higher speed and shorter drying time and thus was used in adjust of water content in second step. As for the accelerated aging test, standardization of initial moisture content of sweet corn seeds (sh2) in 14, 12 and 10%, independent of exposition periods (48, 72 and 96 hours), increased test efficiency when compared with traditional accelerated aging, which allows the lots stratification in different vigor levels. Among the results, the standardization of initial moisture content of sweet corn seeds in 14 and 12% combined with 96 hours period showed more promising in the assessment of physiological quality of sweet corn seeds (sh2).